Why does cold vapor not fog up glasses?

Question

Why does cold vapor not fog up glasses?

In: Chemistry

Answer 1

When you breathe out cold vapor, like from an electronic cigarette or in cold weather, it doesn’t fog up glasses because it’s already in a fine mist form. This mist doesn’t contain tiny droplets of water like warm breath does, which is what causes fogging. Instead, the cold vapor quickly dissipates into the air without leaving enough moisture to condense on your glasses and make them foggy.